Automatic seat mounting arrangement and seat track assembly

ABSTRACT

An automotive seat mounting ( 3 ) comprising relatively slidable members for mounting a seat ( 4 ) within a vehicle such that the seat ( 4 ) can be slidably positioned and moved in a forward (F) and rearward (R) longitudinal direction. The slidable members slidably interconnected at at least two laterally spaced locations. The slidable members are accurately and positively laterally located and interconnected relative to each other in a lateral direction, at only one of said laterally spaced locations. The slidable members may comprise first and second seat track sections ( 8   a   ,10   a ) of an individual seat track assembly ( 6   a ). Alternatively the slidable members may comprise first ( 6   a ) and second ( 6   b ) laterally spaced seat track assemblies.

[0001] This invention relates to an automotive seat mounting arrangement and, in particular, to automotive seat tracks which, in combination with a complementary automotive seat, provide a variety of functions including seat adjustability lengthwise (forward and rearward) of the tracks.

[0002] Typically, an automotive seat is mounted within a vehicle via a pair of laterally spaced seat tracks. Such seat tracks comprise a pair of seat track sections mounted in mutual sliding lengthwise relationship through bearing means disposed therebetween, so that the seat structure mounted on the uppermost track section is slidably position-adjustable in the usual way.

[0003] It will be readily appreciated that structural components such as seat tracks are subject to the usual automotive manufacturing design constraints with respect to economy of manufacture, particularly with respect to ease of construction and manufacturing tolerances. There is a constant requirement for a reduction in manufacturing complexity and, if possible, reduction in the need to adopt high precision tolerances in the dimensional aspects of components produced.

[0004] It will also be appreciated that structural components such as seat tracks are required to be of sufficient structural integrity to withstand the operational loads and requirements. In particular such seat track assemblies must have sufficient structural strength and integrity to withstand the anticipated high crash/impact loading. Such loads are considerable especially when passenger seat restraints (seat belts) are mounted to the seats.

[0005] Whilst providing a secure structural mounting for the seats the seat track assemblies must also allow the seat to be readily and easily slidably adjusted to suit a seat occupant. This requirement for the seat track assembly to permit easy sliding movement to some degree conflicts with the requirement to provide sufficient structural integrity in the mounting of the seat through the seat track.

[0006] Examples of prior proposed seat arrangements are shown in UK Patent applications GB 2,090,127 and GB 1,279,620 as well as in French patent application number FR 2,562,004 and Japanese patent application number JP 52,29,374. These seat track arrangements comprise pairs of interlocking profiled rail members which are profiled and double interlocked along their lengths. Typically each rail comprises a U shaped portion and a flange or further U shaped portion. The flange or U shaped portion of one rail is engaged with the U shaped portion of the other rail, and vice versa to provide the double interlocking of the rails along two laterally spaced lengths of the rails. To ensure accurate location of the rails and so a firm interconnection sets of rollers and bearing blocks are provided at each interlocking location to provide lateral and vertical accurate location of the pair of rails. If such blocks and roller bearings etc are not provided then there is a risk that the rails would in use become disengaged or at the very least there would in use be an unacceptable degree of play within the engagement of the rails and the assembly as a whole. Whilst such arrangements provide suitable seat mounting arrangements the manufacturing tolerances required to produce and assemble the seat tracks are relatively high, with commensurate cost implications, in order that the seat track assemblies operate satisfactorily. If such high tolerances are not maintained then such assemblies are either difficult to assemble, or may jam or seize due to tolerance mismatch and ‘fight’ between the engaged portions restricting sliding of the assemblies. Specifically the arrangement of FR 2562004 requires accurate positioning and high tolerances to ensure that the U shaped portions of the rails are seated within the shoes which provide accurate relative vertical and lateral positioning of the rails. Similarly in the arrangements of JP 5229374, GB 2090127, and GB 1279620 the arrangement of the sets of roller bearings and blocks is such that high manufacturing tolerances are required for the parts of the assembly. Furthermore these arrangements can also be improved generally in terms of cost, structural strength and integrity, and ease of operation.

[0007] According to the present invention there is provided an automotive seat track assembly and seat mounting as defined in the accompanying claims.

[0008] An object of the present invention is to provide improvements in one or more of these respects in relation to the construction and use of automotive seat tracks and/or to provide improvements to seat track assembly arrangements generally.

[0009] In a general aspect of embodiments of the invention there is disclosed an automotive seat mounting comprising relatively slidable members for mounting a seat within a vehicle such that the seat can be slidably positioned and moved in a forward and rearward longitudinal direction. The slidable members slidably interconnected at at least two laterally spaced locations. The slidable members are accurately and positively laterally located and interconnected relative to each other in a lateral direction, at only one of said laterally spaced locations.

[0010] In a particular aspect of embodiments of the invention there is disclosed a seat track mounting arrangement using a pair of laterally spaced assemblies. The pair of seat track assemblies are arranged to achieve the desired result of controlling lost motion or free play or backlash in two directions at right angles (for example upwards and sideways). This is achieved by one of the pair of seat track assemblies, at one lateral side only of the mounting arrangement, having an accurately located sliding or bearing element within the interfitting sections of the seat track assembly. The other seat track assembly, at the other side of the mounting arrangement, does not include the provision for precise lateral locations or guidance since this has been achieved by the seat track assembly on the other, first, side. This is in contrast to previous arrangements in which both seat track assemblies (of a conventional design), at both sides of the seat mounting provide for relatively precise dimensional control in both the vertical and lateral directions. In this way since one of the seat track assemblies is not required to provide precision dimensional control, it is not therefore required to be fabricated to such a high tolerance. Consequently that seat track assembly can be more simply and economically manufactured reducing the overall cost of the mounting arrangement. In addition installation, and location, of the seat mounting is made easier since only the seat track assembly providing the accurate lateral and vertical control needs to be accurately and carefully mounted in the vehicle. The other seat track assembly on the other lateral side only needs to be generally located and mounted to the vehicle at generally the correct position, with a large tolerance being permitted for such location and mounting of that seat track assembly. Furthermore since only one of the seat tack assemblies accurately controls the lateral position of the seat mounting, lateral ‘fight’ between the seat track assemblies due to tolerance mismatches in their mounting within the vehicle, and possible jamming of the seat mounting, can be reduced. Any mismatch in the location and mounting of the seat track assemblies in the vehicle is accommodated by the clearance tolerances in the seat track assembly which does not provide accurate lateral dimensional control.

[0011] This can also be applied to and with each individual seat track assembly. Typically a seat being mounted to the vehicle floor via a pair of seat track assemblies. In a particular embodiment there is disclosed a seat mounting comprising a first seat track section and second seat track section. Each seat track section comprises a first and second parallel spaced apart interconnecting portions. The first and second interconnecting portions of said first seat track section cooperatively and sliding engaging said second and first interconnecting portions of said second seat track sections respectively such that said first and second seat track section are sliding engaged and interconnected along the length of the two parallel spaced interconnecting portions of the seat track sections. The mounting further comprises an accurate lateral locating element to accurately and positively locate only the first interconnecting portion of said first seat track section with the second interconnecting portion of said second seat track section.

[0012] In addition in a further aspect of an embodiment of the invention the relatively slidably disposed seat track sections have substantially identical cross-sectional shapes in the upper and lower portions of the seat track assembly. With such arrangements manufacturing complexity is reduced since both sections can be produced by the same pressing tool instead of the usual requirement for two different such tools and this also reduces the significant tooling costs.

[0013] Furthermore, in the embodiments, the adoption of identical or closely similar seat track sections enables the use of an interfitting arrangement in which the relative disposition of the interfitting portions is such that the combined assembly maximises the section modulus of the assembly thereby efficiently and economically providing improve rigidity, stiffness and strength.

[0014] In a yet further aspect of the present invention there is described a method of installing and assembling a seat track assembly which comprises a first and second slidingly interconnected seat track sections which mount a vehicle seat to a vehicle. The method comprising

[0015] a) providing a temporary locating means between said interconnected seat track sections to accurately locate and align said first and second seat track sections relative to each other;

[0016] b) installing and mounting said seat track assembly with said vehicle;

[0017] c) removing said temporary locating means.

[0018] The temporary locating means preferably comprises wax which is provided to fill the sliding clearances between the first and second slidingly interconnected seat track sections.

[0019] By using a temporary locating means to accurately locate and align the seat track sections relative to each other the seat track sections can be easily and accurately installed within the vehicle whilst still in use providing sufficient operating clearances to allow free sliding of the seat track sections.

[0020] The present invention will now be described by way of example only with reference to the following figures in which:

[0021]FIG. 1 is a schematic perspective part view of a seat and seat mounting incorporating a pair of laterally spaced seat track assemblies according to the present invention;

[0022]FIG. 2 is a more detailed cross sectional view through one of the seat track assemblies shown in figure.

[0023]FIG. 3 is a cross sectional view, similar to FIG. 2, but of an alternative seat track assembly;

[0024]FIG. 4 is a schematic force diagram showing the location forces provided by the respective seat track assemblies of the seat mounting shown in FIG. 1 using the seat track assemblies of FIGS. 2 and 3.

[0025] Referring to FIG. 1 a vehicle seat 4 is slidably, in a lengthwise forward F and rearward R direction, mounted to the floor 2 of a vehicle via a seat mounting arrangement 3. The seat mounting arrangement 3 is arranged to permit the seat 4 to be slid in a forward F and rearward R direction, and the seat 4 can accordingly be positioned in a desired fore and aft position as required by a seat occupant.

[0026] The seat mounting arrangement 3 comprises a pair of laterally spaced seat track assemblies 6 a,6 b. The seat track assemblies 6 a,6 b are mounted on the underside of the seat 4 and are interposed between the base of the seat 4 and vehicle floor 2. The seat track assemblies 6 a,6 b are disposed on opposite lateral sides (left and right relative to a seat occupant) of the seat 4, and extend in a lengthwise (forward F and rearward R) direction generally parallel to, and laterally spaced apart from, each other. Each of the seat track assemblies 6 a,6 b comprises a pair of respective upper and lower seat track sections 8 a,10 a,8 b,10 b. The upper seat track sections 10 a,10 b are attached to the base of the seat 4 via suitable mounting bolts 28 a,28 b whilst the lower seat track sections 8 a,8 b are attached to the floor 2 via suitable mounting blocks 30 a,30 b. The respective upper 10 a,10 b and lower 8 a,8 b seat track sections are arranged, mounted and interconnected in mutual sliding lengthwise relationship, as will be explained further below. The seat track sections 8 a,10 a,8 b,10 b, and seat track assemblies 6 a,6 b formed thereby, interconnect and slidably mount the seat 4 on and to the vehicle floor 2. The respective left 6 a and right 6 b seat track assemblies 6 a,6 b are shown in more detail in FIG. 2.

[0027] Considering the lefthand seat track assembly 6 a shown in cross section and more detail in FIG. 2. The lower seat track section 8 a comprises an elongate channel section with a generally U shaped cross section. The lower seat track section 8 a comprises a pair of parallel spaced apart first 16 a and second 18 a side portions 16 a,18 a which extend from, and are integral with, an interconnecting portion 15 a. The mounting bolts 30 a pass through mounting apertures in the interconnecting portion 15 a to attach and mount the lower seat track section 8 a on the vehicle floor 2, with the side portions 16 a,18 a extending away (upwards) from the floor 2. The second side portion 18 a is longer than the first side portion 16 a and extends further from the interconnecting portion 15 a. A distal edge portion 32 a,34 a of each of the side portions 16 a,18 a of the seat track section 8 a, is in the form of a further, smaller, U section channel which is inverted, with respect to the overall U shape of the seat track section 8 a, such that an open end of the smaller U shaped edge portion 32 a,32 h is directed towards the interconnecting portion 15 a of the seat track section 8 a.

[0028] The upper seat track section 10 a is substantially identical to the lower seat track section 8 a described above. The upper seat track section 10 a comprises a pair of first 12 a and second 14 a side portions interconnected by an integral interconnecting portion 13 a with a second side portion 14 a longer than, and extending further than, a first side portion 10 a. Distal edge portions 31 a,35 a of the side portions 10 a,14 a are also each in the form of a smaller inverted U section channel. As arranged in the assembled seat track assembly 6 a, the upper seat track section 10 a is an inverted version of the lower seat track assembly 8 a, with mounting bolts 28 a interconnecting the upper seat track section to the base of the seat 4.

[0029] The U shaped cross section of the seat track sections 8,10 allows the seat track sections to be easily bolted to the floor 2/seat 4 and the lateral width of the U shaped sections 8,10 is dimensioned so as to accommodate suitable bolts 28,30 or other attachment means.

[0030] As shown in FIG. 2, to form the seat track assembly 6 a, the upper 10 a and lower 8 a seat track sections are oppositely arranged lengthwise to each other, and are disposed in an interfitting, interlocking arrangement. The upper seat track section 10 a is located and mounted above and over the lower seat track section 8 a. The first side portion 16 a of the lower section 8 a extends towards the second portion 14 a of the upper section 10 a, whilst the second portion 18 a of the lower section 8 a extends towards the first portion 10 of the upper section 10 a. The U shaped channel distal edge portions 31 a,32 a,34 a,34 b of the respective side portions of the upper and lower sections 10 a,10 b are accordingly oppositely arranged to interfit, interconnect and slidingly interlock lengthwise respectively with each other. In this way the upper 10 a and lower 8 a seat track sections are operatively, slidably, engaged with each other, along each and both respective lateral sides, to form the seat track assembly 6 a. The arrangement of the smaller U-shaped channel portions on the distal edge portions 31 a,32 a and 34 a,35 a of the side portions and their interfitting arrangement provide, in the assembled assembly 6 a, a suitable means to slidably interconnect the seat track sections 8 a,10 a to form the seat track assembly 6 a.

[0031] The interfitting arrangement of the upper and lower seat track sections 8 a,10 a using the U shaped channel portions also securely interlocks the upper and lower sections 8 a,10 a vertically together. As a result the upper and lower seat track sections 8 a,10 a are securely and structurally connected in a vertical direction. Such an arrangement is capable of being able to withstand the seat loads (generally also vertical) associated with crash/impact loading. The use of twin interlocking portions with the upper and lower seat track sections 8 a,10 a interlocked together along both/twin lateral sides provides a particularly secure structural interconnection of the upper and lower seat track sections. The use of a twin pair of interlocking parts and arrangement also enables the relevant loads to be shared between them with the result that the structural strength requirements of each are less.

[0032] Sets of vertical supporting running blocks or bearing elements 20 a,22 a are disposed along the length of the seat track assembly 6 a. The first set of running blocks or bearing elements 22 a are interposed between, and bear against, an interconnecting portion 15 a of the lower seat track section 8 a and the distal edge portion 31 a of the second side portion 14 a of the upper seat track section 10 a. In operation the distal edge portion 31 a runs along the first set of running blocks 22 a and is supported vertically by them. This maintains the sliding engagement of the distal edge portion 31 a of the second side portion of the upper seat track section 10 a within the distal edge portion 32 a of the first side portion of the lower seat track section 8 a. Similarly the second set of running blocks 20 a is interposed between the interconnecting portion 13 a of the upper seat track section 10 a and the distal edge portion 34 a of the second side portion of the lower seat track section 8 a. This provides similar vertical engagement and location of that side of the seat track assembly 6 a.

[0033] The interfitting of the smaller U shaped edge channels of the distal edge portions 31 a,32 a,34 a,35 a provides a degree of lateral location of the upper and lower seat track sections 10 a,8 a thereby constraining to a certain degree relative lateral movement. There is though a significant degree of lateral clearance between the respective interfitted distal edge portions 31 a,32 a,34 a,35 a. This degree of clearance allows manufacturing, assembly and mounting variations to be accommodated and permits easy relative sliding of seat track sections 10 a,8 a. However in order to provide the required more accurate lateral dimensional control within the left hand seat track assembly 6 a there is a further set of lateral running blocks or bearing elements 24 a.

[0034] As shown these lateral running blocks 24 a substantially fill the clearances between the interfitting distal edge portion 34 a,35 a, leaving a much smaller clearance d, typically of the order of 0.1 mm which is just sufficient to permit sliding These lateral running blocks 24 a ensure that lateral clearances in the seat track assembly 6 a are reduced and ensure that the upper and lower seat track sections 10 a,8 a are accurately laterally located. The lateral running blocks may also to some degree provide further vertical support although this is not their primary function, with the vertical positioning being primarily provided by the vertical running blocks 20 a,22 a.

[0035] As shown only one set of running blocks 24 a are provided between the interfitting distal edge portions 34 a,35 a on one side of the seat track assembly 6 a. It will be appreciated that a further set of lateral running blocks could be provided between the interfitting distal edge portions 31 a,32 a on other side of the seat track assembly 6 a. However this is generally less preferable since using one set of lateral running blocks 24 a on one side only is sufficient to provide the required degree of lateral positioning control. Also by leaving the other side with a larger lateral clearance, dimensional variations of the components, assembly, and mounting can be more easily accommodated.

[0036] In addition with the arrangement shown incorporating only one set of accurate lateral running blocks on one side only of the seat track assembly, it has been found that only one manufacturing dimension 1 between the distal edge portions 34 a,34 b of the upper and lower seat track sections Ba,10 a needs to be accurately controlled during the manufacture of the assembly 6 a in order to provide an acceptable high tolerance overall arrangement and operation. This can be contrasted with conventional arrangements in which high manufacturing tolerance control of a number of key dimensions needs to be provided during manufacture to produce and ensure an overall high tolerance arrangement. The need to accurately control only one dimension during manufacture with this arrangement represents a considerable manufacturing cost saving, whilst making production of a high quality high tolerance seat track assembly economically possible and practicable.

[0037] Furthermore if two sets of lateral running blocks 24 a are used on each side of the seat track assembly 6 a then both sides provide lateral location of the seat track sections 8 a,10 a which may, in use, conflict with each other, due to inaccuracies or variances in manufacturing. This may lead to a degree of ‘fight’ between the lateral location means, resulting in increased friction during sliding and/or possible jamming of the assembly 6 a. The use of a single set of lateral running blocks 24 a within each seat track assembly to provide lateral location of the seat track therefore allows larger manufacturing, assembly and mounting tolerances to be used with the commensurate reduction in cost as well as reducing any tendency for lateral ‘fight’ and so poor sliding of the seat track assembly.

[0038] It will be appreciated though that some of these advantages of using a single set of lateral running blocks 24 a on one side only could be achieved by using one set of accurately controlling and positioning running blocks on one side, with other running blocks located elsewhere having larger tolerances and providing less accurate positional control. In this way any ‘fight’, and other similar problems, would be lessened to some degree by virtue of the larger tolerances of the other set of running blocks as compared to the accurate lateral locating running blocks .

[0039] The lateral running blocks 24 and vertical running blocks 20 a,22 a may comprise solid blocks of a suitable low friction material such as for example PTFE. These allow the seat track sections 8 a,10 a to easily slide relative to each other. Alternatively the running blocks 24 a,20 a,22 a may comprise other suitable bearing arrangements, for example roller bearing assemblies which allow the required relative sliding of the upper and lower tracks. Such bearing assemblies are known to those skilled in the art and indeed are conventionally already used on some conventional prior seat track assemblies.

[0040] Referring to FIG. 3, there is shown an exemplary alternative seat track assembly 6 a′. This is generally the same as that shown in FIG. 2, and described above, and like reference numerals have been used for like features. In this alternative arrangement however the single set of lateral running blocks 24 a are positioned in an alternative location. Specifically the single set of lateral running blocks 24 a′ are mounted upon the upwardly directed tip of the distal edge portion 35 a of the upper seat track section 10 a and are arranged to bear and run against the base of the inverted U shaped channel section of the distal edge portion 34 a of the lower seat track section 8 a. Whilst operating in a similar way to the lateral running blocks 24 a shown as positioned in FIG. 2, this arrangement of FIG. 3 has the advantage of providing improved vertical control and positioning of the upper and lower seat track sections. In this arrangement the lateral running blocks 24 a′ are directly opposed, in a vertical direction, to the vertical running blocks 20 a such that the distal edge portions 34 a of the lower seat track assembly section 8 a is securely clamped therebetween thereby more securely clamping and securing the distal edge portions 34 a, 35 a of the upper and lower seat track sections 8 a,10 a together. Furthermore with the running blocks 20 a,24 a′ in this position, with the vertical and lateral running blocks directly opposed, the key dimension of the assembly 6 a can be more easily and better be controlled.

[0041] It will be appreciated that the lateral running blocks 24 a,24 a′ could in other arrangements be located in different positions, although as mentioned above it is preferable that such running blocks, or at least the accurate lateral positioning running blocks providing the accurate lateral positional and control, are provided on only one side of such arrangements.

[0042] The right hand (as defined from the perspective of a seat occupant) seat track assembly 6 b is substantially identical to the left hand seat track assembly 6 a shown in FIGS. 2 and 3 and described above. Accordingly like reference numerals have been used for like items of this seat track assembly 6 b with a ‘b’ suffix being used to indicate that they relate to the right hand seat track assembly 6 b.

[0043] Considering the overall seat mounting arrangement 3, and for reasons similar to those discussed above (in relation to use of a single set of lateral clearance running blocks 24 in the left hand seat track assembly 6 a) the right hand seat track assembly 6 b as a whole also does not need to provide accurate lateral dimensional control of the seat 4 position. Sufficient accurate dimensional lateral control for the overall seat mounting 3 can be provided by the left hand seat track assembly 6 a alone. Indeed it is preferable for the right hand seat track assembly 6 b to be arranged such that it does not provide accurate lateral dimensional control. In this way the overall seat mounting arrangement can better accommodate manufacturing, assembly and mounting variations. Friction during sliding movement of the seat 4 and potential jamming due to misalignment of the seat track mounting 3 is also reduced. This is in a similar ay to that described above in relation to each individual seat track assembly.

[0044] Accordingly the lateral running blocks 24 b of the right hand seat track assembly 6 b do not provide as accurate lateral control and positioning, with the clearance d associated with these running blocks 24 b being significantly greater than that of the running blocks 24 a of the left hand seat track assembly 6 a. Accordingly typically the clearance d of the right hand seat assembly 6 b is significantly greater than 0.1 mm that is present in the left hand seat track assembly 6 a. Therefore, in the right hand seat track assembly 6 b there is a significant lateral clearance between the interfitting of the distal edge portions 31 b,32 b,34 b,35 b and this seat track assembly 6 b does not provide accurate lateral dimensional control. The seat track assembly 6 b does however provide accurate vertical dimensional control due to the use of the vertical running blocks 20 b,22 b, along with some vertical control though the lateral running blocks 24 b. In alternative embodiments the lateral running blocks 24 b of the left hand seat track assembly 6 b may even be omitted in their entirety.

[0045] In the overall seat mounting 3 therefore, as shown in FIG. 4, both the left hand seat track assembly 6 a and right hand seat track assembly 6 b provide accurate dimensional control and positioning of the seat 4 in the vertical direction as shown by locating force arrows V1 and V2. Accurate lateral dimensional control however is provided by only the left hand seat track assembly 6 a as indicated by locating force arrows L1. This is in a similar fashion to the detailed arrangement in each seat track assembly 6 a,6 b with respect to each individual side of each set track assembly 6 a,6 b. It should be noted that this is an important and significant related yet to some degree distinct aspect of both each seat track assembly 6 a,6 b and of the mounting arrangement 3 as a whole.

[0046] During assembly and installation of the seat 4 and seat mounting 3 within a vehicle and attachment to the vehicle floor 2, wax or some other form of sacrificial material may be provided to fill the sliding clearances between the upper and lower seat track sections of each seat track assembly 6 a,6 b of the mounting 3. Such a material provides a temporary rigid means of locating the upper and lower seat track sections 8,10 relative to each other and ensuring that as the assembly 3 is fitted the upper and lower seat track sections 8,10 are kept in the correct alignment and relative positions. This assists in ensuring that the mounting bolts 28,30 are correctly aligned with mounting features of the vehicle floor 2. In addition it ensures that the seat tracks 6 a,6 b and upper and lower sections 8,10 are correctly installed parallel to each other and correctly relatively spaced apart such that they are free to slide. Once installed and the seat track assemblies slid for the first time the sacrificial material is forced out of the clearances between the sliding upper and lower sections and clearances therebetween. Indeed the sacrificial material, eg wax, is specifically chosen such that this happens with, in the case of a wax, the friction generated by the first sliding operation melting the wax. Consequently once the seat track assemblies 6 a,6 b have been slid for the first time (or initial first few times), following installation, and the sacrificial material removed the design clearances of the seat tracks 6 a,6 b and assembly 3 are reestablished allowing easy and free sliding movement.

[0047] In this seat mounting arrangement 3 the seat track assemblies 6 a,6 b are substantially identical. Furthermore, and significantly, the upper and lower seat track sections 8 a,8 b,10 a,10 b which form the seat track assemblies 6 a,6 b are arranged to be substantially identical and are of the same general configuration. In particular the seat track sections 8 a,8 b,10 a,10 b have the same cross sectional shape and dimensions. This is particularly advantageous since it means that the manufacturing complexity is reduced since all the main sections 8 a,8 b,10 a,10 b can be produced from, for example sheet metal, by the same pressing tooling instead of the usual requirement for two different sets of such tooling required to produce different specific sections of the seat track assembly. Since such pressing tooling costs are significant and can be halved, this represents a significant manufacturing cost saving. The use of identical parts also means that, to a significant extent, the upper 10 a,10 b and lower 8 a,8 b sections of both the left and right hand seat track assemblies 6 a,6 b are interchangeable. Consequently in a manufacturing environment the inventory requirements can be reduced since the numbers of different parts required for the seat mounting 3 is reduced. This also reduces overall costs.

[0048] An additional and significant advantage of the use of identical interfitting upper and lower seat track sections 8,10, produced from a single set of tooling, is that they will still interfit together and operate even if the sections 8,10 manufactured are out of the design tolerance. This is because with the two sections 8,10 being produced from the same tooling, any out of tolerance arising in the manufacture will similarly affect both the upper and lower sections 8,10 produced. Consequently if a dimension in the upper section 10 is larger than the design dimension (eg. the upper track section 10 is laterally wider than design dimension) then the corresponding dimension in the lower section 8 will also be similarly larger, such that in the interfitting arrangement these will compensate and accommodate each other. This can be contrasted with conventional arrangements with different upper and lower sections in which in order to ensure correct interfitting and operation each of the different and differently manufacture sections have to be produced to the exact (within tolerance) dimensions.

[0049] It will be appreciated that the seat track sections 8 a,8 b,l0 a,10 b do not necessarily need to be exactly identical in order to provide the majority of the advantages of the invention, although it is preferred that they are identical since this maximises the advantages described. The identity between the seat track sections 8 a,8 b,10 a,10 b generally only needs to be of a sufficient degree that substantially the same major (and therefore most expensive) tooling, and/or fabrication steps, can be used to fabricate the respective seat track sections 8 a,8 b,10 a,10 b. In general this means that the seat track sections 8 a,8 b,10 a,10 b should have the same cross section. It will also be appreciated that, in alternative embodiments, additional different minor additional components and/or modifications could be made to a base seat track section to produce slightly different respective seat track sections 8 a,8 b,10 a,10 b. Also for example the gauge of metal used to form the upper and lower seat track assemblies 8,10 could be different. Also the blanks from which the seat track sections 8,10 are pressed could vary such that although pressed and bent in the same way within the pressing tooling the tracks 8,10 actually produced vary slightly. In such cases the tooling cost would still be reduced since a common base seat track section is used to form all of the slightly different and modified seat track sections 8 a,8 b,10 a,10 b. Consequently such arrangements with seat track sections 8 a,8 b,10 a,10 b which vary from each other only in minor and/or ancillary respects by including for example additional elements or minor modification differences should be considered as generally identical in the terms of this invention.

[0050] The strength and stiffness of the seat track assemblies 6 a,6 b is a function both of the strength of the material (typically sheet metal) used to form the section 8 a,8 b,10 a,10 b and the geometrical arrangement of the assemblies and seat track assemblies 6 a,6 b. The strength provided by the geometric arrangement of a section is indicated by the Engineering, or section, Modulus I and is a function of the width w multiplied by the cubed height h of a section (i.e. I=w×h³). The offset geometry of the track sections 8 a,8 b,10 a,10 b with the first and second side portions being of different lengths, and arranging the sections 8 a,10 a,8 b,10 b in an opposite facing, offset, complementary manner with the first side portion of the upper section 10 a,10 b above the second side portion of the lower section 8 a,8 b (and vice versa) the modulus I of the seat track assembly 6 a,6 b is most efficiently and effectively maximised whilst using identical upper and lower sections 8 a,8 b,10 a,10 b.

[0051] It will be appreciated that whilst the seat track sections shown 8 a,8 b,10 a,10 b and described are particularly preferable, in other embodiments of the invention alternative detailed cross sectional shapes and profiles can be to provide such identical upper and lower complementary engaging seat track sections 6 a,6 b. Also although the seat track sections have been shown and described as upper and lower sections, it will be appreciated that in other embodiments the seat track sections 8 a,10 a could be disposed in a side by side relationship (i.e. the seat track assembly shown could be rotated through 90 degrees about its elongate longitudinal axis).

[0052] The seat mounting 3, and in particular either or both of the seat track assemblies 6 a,6 b typically also include suitable locking and drive mechanisms and features (not shown). Such locking and drive mechanisms (which provide means to lock and drive sliding adjustment of the position of a seat 4 mounted via mounting tracks) are generally known and can be readily incorporated into the seat mounting arrangement 3 described. Consequently such mechanisms will not be described in detail. 

1. An automotive seat mounting comprising relatively slidable members for mounting a seat within a vehicle such that the seat can be slidably positioned and moved in a forward and rearward longitudinal direction, the slidable members slidably interconnected at at least two laterally spaced locations; characterized in that the slidable members are accurately and positively laterally located and interconnected relative to each other in a lateral direction, at only one of said laterally spaced locations.
 2. An automotive seat mounting as claimed in claim 1 in which said slidable members comprise part of an individual seat track assembly.
 3. An automotive seat mounting as claimed in claim 1 in which said slidable members comprise first and second seat track assemblies.
 4. An automotive seat mounting as claimed in any one of claims 1 comprising an accurate lateral positioning bearing element located at only one of said laterally spaced locations.
 5. An automotive seat mounting arrangement as claimed in claim 4 further comprising a further lateral positioning bearing element located at said other side, said further lateral positioning bearing element adapted to provide only limited lateral location of said slidable members as compared to said accurate lateral positioning bearing element.
 6. An automotive seat mounting as claimed in any one of claims 1 in which the slidable members are accurately and positively vertically located and interconnected in a substantially vertical direction relative to each other at both of said at least two laterally spaced locations.
 7. An automotive seat track assembly for slidably mounting a seat within a vehicle such that the seat can be slidably positioned and moved in a forward and rearward direction, the seat track assembly comprising a pair of elongate seat track sections which are co-operatively arranged and interconnected such that they are operatively slidable with respect to each other with one of the said seat track sections arranged to be connectable to the seat whilst the other respective seat track section is arranged to be connectable to the vehicle; characterised in that the seat track sections are of substantially the same cross sectional shape such that they can be formed from substantially the same general tooling.
 8. An automotive seat mounting as claimed in claim 2 in which said slidable members comprise a pair of slidably interconnected cooperating seat track sections which are substantially identical in cross section.
 9. An automotive seat mounting as claimed in claim 2 in which the cross sectional shape of the seat track section is offset, and the seat track sections are interconnected such that the offset cross sectional shape of the seat track sections is arranged in a complementary manner within the seat track assembly.
 10. An automotive seat track assembly as claimed in claim in which the seat track sections are interconnected along at least part of their elongate length.
 11. An automotive seat track assembly as claimed in claim in which the seat track sections comprise cooperating interfitting elements which are arranged in the assembly in an interfitting arrangement to slidably interconnected the seat track sections to each other.
 12. An automotive seat track assembly as claimed in claim in which the interfitting arrangement interconnects the seat track sections at laterally spaced positions disposed towards opposite lateral sides of the cross section of the seat track sections.
 13. An automotive seat track assembly as claimed in claim in which the interfitting elements comprise substantially U shaped co-operatively engaging edge portions of the respective seat track sections.
 14. An automotive seat track assembly as claimed in claim in which the seat track sections are of a generally U shaped cross section.
 15. An automotive seat track assembly as claimed in claim in which each of the seat track sections, in cross section, comprises respective first and second side portions interconnected by and extending from an interconnecting portion.
 16. An automotive seat track assembly as claimed in claim in which the second side portion is longer than the first side portion and extends further from the interconnecting portion such that the cross section of the seat track section is thereby offset.
 17. An automotive seat track assembly as claimed in claim in which the first side portion of one of the seat track sections is interconnected to the second side portion of the other seat track section.
 18. An automotive seat mounting as claimed in claim 3 said first and second seat track assemblies are laterally spaced and are arranged to be disposed at either side of the seat.
 19. An automotive seat mounting arrangement as claimed in claim 18 in which one of the pair of seat track assemblies, at one lateral side only of the mounting arrangement, is adapted to provide accurate lateral location and guidance of the relatively slidable seat track sections, the other seat track assembly, at the other side of the mounting arrangement not being adapted to provide accurate lateral location and/or guidance.
 20. A seat mounting comprising a first seat track section and second seat track section; each seat track section comprising a first and second parallel spaced apart interconnecting portions, said first and second interconnecting portions of said first seat track section cooperatively and sliding engaging said second and first interconnecting portions of said second seat track sections respectively such that said first and second seat track section are slidingly engaged and interconnected along the length of the two parallel spaced interconnecting portions of the seat track sections; the mounting further comprising an accurate lateral locating element to accurately and positively locate only the first interconnecting portion of said first seat track section with the second interconnecting portion of said second seat track section.
 21. A method of installing and assembling a seat track assembly which comprises a first and second slidingly interconnected seat track sections which mount a vehicle seat to a vehicle; the method comprising a) providing a temporary locating means between said interconnected seat track sections to accurately locate and align said first and second seat track sections relative to each other; b) installing and mounting said seat track assembly with said vehicle; c) removing said temporary locating means.
 22. A method as claimed in claim 21 wherein the temporary locating means comprises wax which is provided to fill the sliding clearances between the first and second slidingly interconnected seat track sections. 